U.S. patent application number 11/731061 was filed with the patent office on 2008-10-02 for fabric with improved heat resistance and methods of making same.
This patent application is currently assigned to Ironclad Performance Wear Corp.. Invention is credited to Eric M. Jaeger, Minho Kim.
Application Number | 20080242176 11/731061 |
Document ID | / |
Family ID | 39795243 |
Filed Date | 2008-10-02 |
United States Patent
Application |
20080242176 |
Kind Code |
A1 |
Jaeger; Eric M. ; et
al. |
October 2, 2008 |
Fabric with improved heat resistance and methods of making same
Abstract
Fabric impregnated with polysiloxane. The fabric may be leather,
synthetic leather or suede. Alternatively the fabric may be made
from aramid or oxidized polyacrylic/nitride fibers. One method of
making this fabric is to mix liquid silicone rubber; impregnate the
fabric with the liquid chemical; and heat the fabric at
120-200.degree. C. for 10-150 seconds. Another method of making the
fabric is to mix liquid silicone rubber or a mixture of liquid
silicone rubber and catalyzed polyurethane with fibers and heat the
mixture at 120-200.degree. C. for 10-150 seconds. Fibers may be
polyester microfibers, nylon microfibers, suede, aramid, oxidized
polyacrylic/nitride, and mixtures of these fibers.
Inventors: |
Jaeger; Eric M.; (El
Segundo, CA) ; Kim; Minho; (Kyunggi-do, KR) |
Correspondence
Address: |
IRVING KESCHNER
21535 HAWTHORNE BOULEVARD, SUITE 385
TORRANCE
CA
90503
US
|
Assignee: |
Ironclad Performance Wear
Corp.
|
Family ID: |
39795243 |
Appl. No.: |
11/731061 |
Filed: |
March 30, 2007 |
Current U.S.
Class: |
442/139 ;
427/387; 442/136; 442/152; 442/164; 442/167; 442/169; 442/59 |
Current CPC
Class: |
D06M 11/45 20130101;
Y10T 442/2902 20150401; D06M 11/44 20130101; D06M 11/47 20130101;
D06M 11/74 20130101; Y10T 442/2861 20150401; Y10T 442/2656
20150401; Y10T 442/2631 20150401; D06M 15/564 20130101; D06M
2101/26 20130101; Y10T 442/2885 20150401; Y10T 442/2762 20150401;
D06M 2101/36 20130101; D06M 15/643 20130101; D06M 2200/30 20130101;
Y10T 442/20 20150401 |
Class at
Publication: |
442/139 ;
427/387; 442/136; 442/152; 442/164; 442/167; 442/169; 442/59 |
International
Class: |
B32B 27/02 20060101
B32B027/02; B05D 3/02 20060101 B05D003/02; B32B 5/02 20060101
B32B005/02 |
Claims
1. A material with improved heat resisting properties comprising a
fabric impregnated with a polysiloxane.
2. The material of claim 1 in which said polysiloxane includes a
flame retardant.
3. The material of claim 2 in which said flame retardant is
selected from the group consisting of platinum compounds, carbon
black, aluminum trihydrate, antimony compounds, zinc compounds,
ceric compounds, and mixtures thereof.
4. The material of claim 1 in which said fabric is selected from
the group consisting of leather, synthetic leather and suede.
5. The material of claim 1 in which said fabric is selected from
the group consisting of woven, non-woven, knitted and compressed
non-woven.
6. The material of claim 1 in which said fabric is made from fibers
selected from the group consisting of aramid and oxidized
polyacrylic nitride.
7. The material of claim 1 in which said polysiloxane penetrates
from 5 to 50% of the fabric thickness as measured from a surface of
said fabric.
8. The material of claim 1 in which said polysiloxane comprises
from 5 to 75% of total material weight.
9. A material with improved heat resisting properties comprising a
fabric impregnated with a polysiloxane and a polyurethane.
10. The material of claim 9 in which said polysiloxane includes a
flame retardant.
11. The material of claim 10 in which said flame retardant is
selected from the group consisting of platinum compounds, carbon
black, aluminum trihydrate, antimony compounds, zinc compounds,
ceric compounds, and mixtures thereof.
12. The material of claim 9 in which said fibers are selected from
the group consisting of polyester microfibers, nylon microfibers,
aramid, oxidized polyacrylic nitride, and mixtures thereof.
13. The material of claim 9 in which said polysiloxane penetrates
from 5 to 50% of the fabric thickness as measured from a surface of
said fabric.
14. The material of claim 9 in which said polysiloxane comprises
from 5 to 75% of total material weight.
15. A method of providing a fabric with improved heat resistance
comprising the steps of: a) obtaining a liquid, two component
silicone rubber; b) mixing said components in a ratio calculated to
cause curing of said silicone rubber; c) impregnating a surface of
said fabric with said mixture; and d) heating said fabric at
120-200.degree. C. for 10-150 seconds.
16. The method of claim 15 further comprising the step of adding a
flame retardant to said silicone rubber.
17. The method of claim 16 in which said flame retardant is
selected from the group consisting of platinum compounds, carbon
black, aluminum trihydrate, antimony compounds, zinc compounds,
ceric compounds, and mixtures thereof.
18. The method as claimed in claim 15 in which said fabric is
selected from the group consisting of leather, synthetic leather
and suede.
19. The method as claimed in claim 15 in which said fabric is
selected from the group consisting of woven, non-woven, knitted and
compressed non-woven.
20. The method as claimed in claim 15 in which said fabric is made
from fibers selected from the group consisting of aramid and
oxidized polyacrylicnitride.
21. The method of claim 15 in which said silicone rubber penetrates
from 5 to 50% of the fabric thickness as measured from a surface of
said fabric.
22. The method of claim 15 in which said silicone rubber comprises
from 5 to 75% of total material weight.
23. A method of fabricating a fabric with improved heat resistance
comprising the steps of: a) obtaining liquid, two component
silicone rubber; b) obtaining fabric fibers; c) mixing said
components in a ratio calculated to cause full vulcanization of
said silicone rubber; d) mixing said fabric fibers with said
mixture; and e) heating said mixture at 120-200.degree. C. for
10-150 seconds; whereby said silicone rubber cross links.
24. The method of claim 23 further comprising the step of adding a
flame retardant to said silicone rubber.
25. The method of claim 24 in which said flame retardant is
selected from the group consisting of platinum compounds, carbon
black, aluminum trihydrate, antimony compounds, zinc compounds,
ceric compounds, and mixtures thereof.
26. The method as claimed in claim 23 in which said fibers are
selected from the group consisting of polyester microfibers, nylon
microfibers, suede, aramid, oxidized polyacrylic nitride, and
mixtures thereof.
27. A method of fabricating a fabric with improved heat resistance
comprising the steps of: a) obtaining liquid, two component
silicone rubber; b) obtaining two part polyurethane; c) obtaining
fabric fibers; d) mixing said components in a ratio calculated to
cause full vulcanization of said silicone rubber; e) mixing said
parts in a ratio designed to cause full curing of said
polyurethane; f) mixing said fabric fibers with said mixed
components and said mixed parts; and g) heating said mixture at
120-200.degree. C. for 10-150 seconds; whereby said silicone rubber
and said polyurethane cross link.
28. The method of claim 27 further comprising the step of adding a
flame retardant to said silicone rubber.
29. The method of claim 28 in which said flame retardant is
selected from the group consisting of platinum compounds, carbon
black, aluminum trihydrate, antimony compounds, zinc compounds,
ceric compounds, and mixtures thereof.
30. The method as claimed in claim 27 in which said fibers are
selected from the group consisting of polyester microfibers, nylon
microfibers, suede, aramid, oxidized polyacrylic nitride, and
mixtures thereof.
Description
BACKGROUND OF THE INVENTION
[0001] (1) Field of the Invention
[0002] The present invention relates to the field of fabrics, and
more particularly to fabrics that are treated for heat protection
by impregnation with polysiloxane.
[0003] (2) Description of the Related Art
[0004] A number of heat protected gloves have been available in the
prior art. For example, leather gloves having synthetic and natural
insulation, knit cotton gloves, oven mitts using cotton or other
fiber fabrics with insulation, silicon molded grips and mitts,
aluminized coating on cotton, wool, aramid fibers (such as
Kelvar.RTM. or Nomex.RTM.) and racing gloves (combination of cut
and sewn aramid fabrics and leather) all have some heat protection
features. In some glove applications silicone has been printed or
screen printed on the surface of the glove.
[0005] U.S. Pat. No. 7,086,092 to Carey et al. discloses a glove
having a heat insulating barrier which is removably inserted into a
pocket or pouch positioned adjacent the back of a user's hand. The
insulating barrier reduces heat conduction from the back side of
the hand enabling the user's hand to remain warm in cold
environments. The heat insulating barrier is constructed, for
example, of closed-cell neoprene with fleece laminated
therewith.
[0006] U.S. Pat. No. 5,598,582 to Andrews et al. discloses a hand
covering in the form of a glove which is water proof and provides
protection against cutting, puncturing and lacerations as well as
thermal insulation for protection against burning of the user's
hand when grasping hot objects. A raised silicone pattern is formed
on the palm portion of the glove to enhance the heat insulating and
gripping abilities of the hand covering.
[0007] U.S. Pat. No. 6,021,523 to Vero discloses a hand covering
which is heat and abrasion resistant. The hand covering is
processed by utilizing a fabric formed with conditioned KEVLAR
wound with a top cover of a yarn selected from the group consisting
of PANOX and VECTRAN.
[0008] U.S. Pat. No. 7,000,257 to Bevier discloses a structure of a
glove that includes a first material element and a second material
element. The material elements are separate from each other and
positioned adjacent each other, and the material elements are
joined with a stitchless configuration, that may be a stitchless
seam. An adhesive element may be secured to each of the first
material element and the second material element to form the
stitchless configuration. The adhesive element may be a polymer,
and more particularly, may be a thermoplastic polymer.
[0009] U.S. Pat. No. 7,100,212 to Jaeger discloses a fitted glove
structure that incorporates a molded rubber palm piece that has a
portion which extends over certain of the glove fingertips to the
back piece in a manner to increase wearer comfort and protection
and to enhance the object pick up capabilities of the glove.
[0010] United States Patent Application Publication 2003/0148693 to
Erb et al. discloses an insulating fabric which substantially
prevents propagation of fire utilizing a blend of modified aluminum
oxide-silica fibers and organic fibers in a multi-layer
blanket.
[0011] Although the prior art glove and fabric constructions noted
above provided heat protection, when the glove is intended for work
applications certain disadvantages arise. For example, if natural
or synthetic material is used as the glove palm material, the
following table illustrates the properties associated with
each:
TABLE-US-00001 Resistance Dexterity To After Heat Abrasion Glove
Type Dexterity Shrinkage Exposure Resistance Durability
Breathability Test Method EN 420.sup.1, EN 13844, EN 420, EN 388,
ASTM D737 ASTM ASTM ASTM F210 ASTM F210.sup.2 D6076 D3884 Leather
Low Poor Poor High High Poor Leather Insulated Low Poor Poor High
High Poor Cotton Knit High High High Low Low High Oven Mitts Low
High High Low Low Low Silicone Molded Low High High Low Low Low
Grips And Mitts Aluminum Low Moderate Moderate Low Moderate Low
Coated Leather Or Cotton Aramid Knits High High High Low Low High
(Nomex .RTM., Kevlar .RTM.) O-PAN Knit High High High Low Low High
(Oxidized Polyacrylic Nitride) Racing High Poor Poor Low Moderate
Moderate Gloves (Leather And Aramid) Dexterity Contact Convective
after Flame Heat Heat Splash Glove Type Washing Protection
Protection Protection Protection Grip Test Method EN 420, EN 407,
EN 407, EN 407 ISO ASTM ASTM ASTM ASTM 13994.sup.3 D6183 F210 F1358
F1060 Leather Low Moderate Good Good High High Leather Insulated
Low Moderate High High High Good Cotton Knit High Low Low To Low
Low Low Moderate Oven Mitts Low Low High High High Low Silicone
Molded Low Good Good Good High Good Grips And Mitts Aluminum Coated
Low Moderate High High High Low Leather Or Cotton Aramid Knits High
High Good Low Low Low (Nomex .RTM., Kevlar .RTM.) O-PAN Knit
(Oxidized High High Good Low Low Low Polyacrylic Nitride) Racing
Gloves Low High Moderate Low to Low High (Leather And Moderate
Aramid) .sup.1EN standards are controlled by CEN, the European
Committee for Standardization, Brussels, Belgium. .sup.2ASTM
standards are controlled by ASTM International, West Conshohocken,
PA. .sup.3ISO standards are controlled by the International
Organization for Standardization, Geneva, Switzerland.
[0012] Development of a fabric with improved heat resistance
represents a great improvement in the field of fabrics and
satisfies a long felt need of clothing and equipment
manufacturers.
[0013] What would be desired is to provide a glove palm material
which is heat resistant and which has as many as possible of the
desirable characteristics and properties noted in the table
above.
SUMMARY OF THE INVENTION
[0014] The present invention is fabric impregnated with
polysiloxane which imparts improved heat resistance properties.
While most useful for glove construction the instant invention can
be used in any application where heat resistance is important.
[0015] The fabric may be synthetic leather, leather or suede.
Alternatively the fabric may be made from aramid or oxidized
polyacrylic nitride fibers. The polysiloxane penetrates from 5 to
50% of the fabric thickness as measured from the surface of the
fabric. Penetration may be accomplished from one or both surfaces
of the fabric. The polysiloxane comprises from 5 to 75% of total
material weight. This process may be used to penetrate woven,
knitted, non-woven fabric and compressed non-woven fabric.
[0016] One method of making this fabric is to obtain a liquid, two
component silicone rubber; mix the two components in a ratio
designed to cause curing, impregnate the surface of the fabric with
the mixture; and heat the fabric at 120-200.degree. C. for 10-150
seconds.
[0017] Another method of making the fabric is to obtain a liquid,
two component silicone rubber; mix the two components in a ratio
designed to cause curing, mix this mixture with fibers and heat the
mixture at 120-200.degree. C. for 10-150 seconds. Fibers may be
polyester microfibers, nylon microfibers, aramid and oxidized
polyacrylic/nitride, and mixtures of these fibers.
[0018] A third method of making the fabric is to obtain a liquid,
two component 5 silicone rubber; mix the two components in a ratio
designed to cause curing, mix this mixture with fibers and
catalyzed polyurethane and heat the mixture at 120-200.degree. C.
for 10-150 seconds. Fibers may be polyester microfibers, nylon
microfibers, suede, aramid and oxidized polyacrylic/nitride, and
mixtures of these fibers.
[0019] If used in glove construction, at least the palm portion of
the glove is fabricated from heat resistant material in accordance
with this invention. Preferably, the uncured silicone rubber
mixture is applied to synthetic leather and then heated for a
period of time. The uncured silicone rubber mixture penetrates the
fabric from one or both surfaces and then polymerizes. This results
in a chemically cross linked elastomeric solid within the body of
the fabric. The impregnated material is then cut into a pattern
which corresponds to a glove palm piece. The glove is then
fabricated by sewing the palm piece to a glove back piece in a
conventional manner. The resultant glove is heat protected yet has
the dexterity of a non heat protected glove. Protrusions may be
formed on the glove surface to provide for additional heat
protection. An example of protrusions that may be utilized is shown
in U.S. Pat. No. 5,598,582. Alternatively, the protrusions may
produce a nubby surface.
[0020] Gloves made with the material of this invention have a
smooth surface and increased grip (i.e. frictional properties) and
are visually pleasing. The following chart compares their
properties to those of other materials in more detail.
TABLE-US-00002 Low Stays Shrinkage Durable Flexible High High After
After After High Durability Glove Heat Heat Heat Abrasion For
Working Good Vapor Material Dexterity Exposure Exposure Exposure
Resistance Applications Transmission Washable Natural No No Yes No
Yes Yes No No Leather Synthetic Yes Yes No No Yes Yes Yes Yes
Leather Instant Yes Yes Yes Yes Yes Yes Yes Yes Invention Low
Resists Duration, Moderate Moderate Melting Low Temp Convective
Conductive Adaptable To Good after Heat Flame Heat Heat Many
Styles, Splash Good Material Exposure Protection Protection
Protection Configurations Protection Grip Natural Yes Yes Yes Yes
Yes Yes No Leather Synthetic No No Yes No Yes Yes Yes Leather
Instant Yes Yes Yes Yes Yes Yes Yes Invention
[0021] An appreciation of the other aims and objectives of the
present invention and an understanding of it may be achieved by
referring to the accompanying description of a preferred
embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] While the present invention is described herein with
reference to illustrative embodiments for particular applications,
it should be understood that the invention is not limited thereto.
Those having ordinary skill in the art and access to the teachings
provided herein will recognize additional modifications,
applications, and embodiments within the scope thereof and
additional fields in which the present invention would be of
significant utility.
[0023] For purposes of clarification, a polyurethane is any polymer
consisting of a chain of organic units joined by urethane links. It
is widely used in flexible and rigid foams, durable elastomers,
high performance adhesives and sealants, fibers, seals, gaskets,
condoms, carpet underlay, and hard plastic parts. Polyurethane
products are often called "urethanes". They should not be confused
with the specific substance urethane, also known as ethyl
carbamate. Polyurethanes are not produced from ethyl carbamate, nor
do they contain it.
[0024] The main polyurethane producing reaction is between a
diisocyanate (aromatic or aliphatic) and a polyol, typically a
polyethylene glycol or polyester polyol, in the presence of
catalysts and surfactants. In the case of foams materials for
controlling the cell structure are also added. Polyurethane can be
made in a variety of densities and hardnesses by varying the type
of monomer(s) used and adding other substances to modify their
characteristics, notably density, or enhance their performance.
Other additives can be used to improve the fire performance,
stability in difficult chemical environments and other properties
of the polyurethane products.
[0025] Though the properties of the polyurethane are determined
mainly by the choice of polyol, the diisocyanate exerts some
influence. The cure rate is influenced by the functional group
reactivity and the number of functional isocyanate groups.
Mechanical properties are influenced by the functionality and the
molecular shape. The choice of diisocyanate also affects the
stability of the polyurethane upon exposure to light. Polyurethanes
made with aromatic diisocyanates yellow with exposure to light,
whereas those made with aliphatic diisocyanates are stable.
[0026] Softer, more elastic, and more flexible polyurethanes result
when linear difunctional polyethylene glycol segments, commonly
called polyether polyols, are used to create the urethane links.
This strategy is used to make spandex elastomeric fibers and soft
rubber parts, as well as foam rubber. More rigid products result if
polyfunctional polyols are used, as these create a
three-dimensional cross-linked structure which, again, can be in
the form of a low-density foam.
[0027] Two part polyurethanes, one containing the diisocyanate and
the other containing the polyol, are available commercially. The
parts are mixed in the correct proportions to produce a catalyzed
mixture which then cross links or cures usually with application of
heat.
[0028] For purposes of clarification a silicone or siloxane is any
of the class of compounds containing the structural unit
R.sub.2SiO, where R is an organic group or hydrogen. Polysiloxanes
are polymers with the chemical formula [R.sub.2SiO].sub.n. Aramid
is a long-chain synthetic polyamide in which at least 85% of the
amide linkages (--CO--NH--) are attached directly to two aromatic
rings. Polyesters are condensation polymers, which contain the
ester functional group in their main chain. Two of the most
important synthetic polyesters are polycarbonates and polyethylene
terephthalate (PET). Microfiber is fiber with strands less than one
denier.sup.4. 4 A denier is a unit of weight indicating the
fineness of fiber filaments and yarns and is equal to one gram per
9000 meters.
[0029] According to ASTM D1418 there are various classes of
silicone rubbers. These are outlined in the following table.
TABLE-US-00003 Class Description Application MQ Silicone rubbers
having only methyl Not commonly used groups on the polymer chain
(polydimethyl siloxanes) VMQ Silicone rubbers having methyl and
vinyl General purpose substitutions on the polymer chain PMQ
Silicone rubbers having methyl and Extremely low phenyl
substitutions on the polymer chain temperature applications Not
commonly used PVMQ Silicone rubbers having methyl, phenyl Extremely
low and vinyl substitutions on the polymer temperature chain
applications FVMQ Silicone rubbers having fluoro, methyl
Applications and vinyl substitutions on the polymer involving fuel,
oil chain and solvent resistance.
[0030] There are three main industrial classifications of silicone
rubbers:
[0031] High Temperature Vulcanizing (HTV)--Sometimes called heat
curable, these are usually in a semi-solid gum form in the uncured
state. They require rubber-type processing to produce finished
items.
[0032] Room Temperature Vulcanizing (RTV)--Usually come as a
flowable liquid and are used for sealants, mould making,
encapsulation and potting. These materials are not generally used
as conventional rubbers.
[0033] Liquid Silicone Rubbers (LSR)--Sometimes called heat curable
liquid materials, these materials are processed on specially
designed injection molding and extrusion production equipment.
[0034] The most common method for preparing silicone precursors
involves reacting a chlorosilane with water. This produces a
hydroxyl intermediate, which condenses to form a polymer-type
structure. The basic reaction sequence is represented as:
##STR00001##
[0035] This is the favored route although other raw materials such
as alkoxysilanes can be used. Chlorosilanes and other silicone
precursors are synthesized using the "Direct Process", involving
the reaction of elemental silicone with an alkyl halide thus,
[0036] Si+RX.fwdarw.R.sub.nSiX.sub.4-n (where n=0-4)
[0037] Preparation of silicone rubbers requires the formation of
high molecular weight (generally greater than 500000 g/mol). To
produce these types of materials requires di-functional precursors,
which form linear polymer structures. Mono and tri-functional
precursors form terminal structures and branched structures
respectively.
[0038] With the exception of RTV and liquid curing systems,
silicone rubbers are usually cured using peroxides such as benzoyl
peroxide, 2,4-dichlorobenzoyl peroxide, t-butyl perbenzoate and
dicumyl peroxide. Alkyl hydroperoxides and dialkyl peroxides have
also been used successfully with vinyl containing silicones.
Platinum containing catalysts are used in medical applications.
[0039] Hydrosilylation or hydrosilation is an alternative curing
method for vinyl containing silicones and utilizes hydrosilane
materials and platinum containing compounds for catalysts. It is a
2-part process requiring mixing of 2 separate components, with the
resulting material having a limited shelf life. Curing does not
produce volatiles and heat cured conventional silicones with high
tear strengths can be cured in this way.
[0040] Reinforcing fillers are added to improve the otherwise poor
tensile strength of silicones. Silica, in the form of silica fume
with particle sizes in the range 10-40 nm is the most preferred
filler, although carbon black has been used. Fillers do interact
with the vulcanizate, forming a pseudo-vulcanization. This can
occur either during mixing (creep hardening) or in storage (bin
ageing).
[0041] Although milling can break down these structures, it is also
common to add structure control additives to combat these
reactions. Examples of these materials are siloxane-based compounds
such as diphenylsilane and pinacoxydimethylsilane.
[0042] Silicones have better fire resistant properties than natural
rubbers. This property can be improved by the addition flame
retardant additives such as platinum compounds, carbon black,
aluminum trihydrate, antimony compounds, zinc compounds or ceric
compounds. Further improvement in fire resistance may be achieved
by incorporating chlorine functional groups on the polymer chain.
It should be noted that carbon black addition also increases
electrical conductivity.
[0043] Ferric oxide may also be added to improve heat stability.
Titanium dioxide and other organometallic compounds are used as
pigments.
[0044] Liquid silicone rubbers are two-part systems, supplied
deaerated ready for use. Precursors are in one part and curing
agents are in the other. They cure into a polysiloxane after mixing
the two separate portions. Curing is often complete in as little as
a few seconds at temperatures of about 200.degree. C. and
post-curing is not usually required. Varying the ratio of precursor
to curing agent varies the viscosity of the mixed liquid.
[0045] The process of this invention can be applied to any woven or
non woven fabric including commercial synthetic leather and suede.
Synthetic leather is a compressed, non-woven fabric made of
polyester or nylon microfibers in a binder, which is typically
polyurethane. The ratio of fiber to binder ranges from 60/40 to
80/20. The synthetic leather can be dyed or otherwise surface
treated.
[0046] The viscosity of the mixed liquid silicone rubber is
adjusted to ensure proper penetration into the fabric. This can be
achieved by adjusting the ratio of precursor to curing agent.
Alternatively or additionally viscosity can be adjusted by addition
of a thinner, such as heptane, acetone, or alcohol. The mixed or
catalyzed liquid silicone rubber is spread onto one or both
surfaces of the fabric. The mixed silicone rubber is then allowed
to penetrate into the fabric. Methods such us squeegeeing through a
screen have been found helpful in controlling the amount of
silicone rubber applied to a surface. Next the treated fabric is
heated at 120-200.degree. C. for 10-150 seconds which causes the
liquid silicone rubber to cure into polysiloxane. This results in a
cross linked elastomer matrix within the fabric.
[0047] Other methods of introducing mixed, liquid silicone rubber
into woven or non-woven fabric are of course possible, including
introduction of mixed silicone rubber during the original
manufacture of the fabric. In this case the typical polyurethane
binder of synthetic leather is replaced completely or partially
with mixed, liquid silicone rubber.
[0048] The desired result is penetration of the polysiloxane into
the fabric, not layering of the polysiloxane on top of the fabric.
Polysiloxane penetration into surface from either side is 5 to 50
percent of total material thickness. Resulting concentration by
weight is 5 to 75 percent of total material weight. This represents
an addition of 5 to 300 percent by weight of fabric before
impregnation.
[0049] If the polysiloxane is layered on top of the fabric this
will result in loss of breathability, poor grip on wet surfaces and
lower heat durability. Also the fabric underneath will melt and
stiffen after heat exposure. If the polysiloxane does not penetrate
well into the fabric this will result in lower heat durability.
EXAMPLE
[0050] A piece of synthetic leather was impregnated with
polysiloxane using the process of this invention. The liquid
silicone rubber used was SJS-2002, supplied by Sejin Silicone Co.
Ltd. Samples were cut from the impregnated fabric with a sharp
surgical blade and coated with gold-palladium to prevent charging.
The samples were subjected to scanning electro-microscopic
examination. It was found that the polysiloxane had penetrated into
the fabric 9.9 to 24.1 percent of the fabric thickness as measured
from the surface.
[0051] It was also found that the concentration by weight of
polysiloxane was 28-29 percent. This represents an increase of
39-41 percent by weight over the weight of the fabric before
impregnation. The impregnated sample had the following
properties:
TABLE-US-00004 Low Stays High Shrinkage Durable Flexible High High
Durability Glove After Heat After Heat After Heat Abrasion For
Working Good Dexterity Exposure Exposure Exposure Resistance
Application Breathability Washable Yes Yes Yes Yes Yes Yes Yes Yes
Low Duration High Heat Low Temp Moderate Moderate Adaptable To Many
Flame Flame Convective Radiant Heat Styles, Good Splash Good
Protection Protection Heat Protection Protection Configurations
Protection Grip No Yes Yes Yes Yes Yes Yes
[0052] Test methods used included ASTM F1790 (Cut Protection
Performance, ASTM F1060 (Thermal Protective Performance), ASTM
F1358 (Flame Impingement), and a modified version of ASTM F1060
(Thermal Protection at Various Temperatures).
[0053] Thus, the present invention has been described herein with
reference to particular embodiments for a particular application.
Those having ordinary skill in the art and access to the present
teachings will recognize additional modifications, applications and
embodiments within the scope thereof.
[0054] It is therefore intended by the appended claims to cover any
and all such applications, modifications and embodiments within the
scope of the present invention.
* * * * *